Editing Impala (section)

==Taxonomy and evolution==
{{see also|List of bovids}}
The impala is the [[monotypic species|sole member]] of the genus ''Aepyceros'' and belongs to the [[family (biology)|family]] [[Bovidae]]. It was first [[scientific description|described]] by German zoologist [[Martin Hinrich Carl Lichtenstein]] in 1812.<ref name =MSW3>{{MSW3 Artiodactyla | id = 14200488 | pages = 673}}</ref> In 1984, palaeontologist [[Elisabeth Vrba]] opined that the impala is a [[sister taxon]] to the [[Alcelaphinae|alcelaphines]], given its resemblance to the [[hartebeest]].<ref name="vrba">{{cite book |last1 = Vrba |first1 = E.S. |editor1-last = Eldredge |editor1-first = N. |editor2-last = Stanley |editor2-first = S.M. |title = Living Fossils |date = 1984 |publisher = Springer |location = New York, USA |isbn = 978-1-4613-8271-3 |chapter = Evolutionary pattern and process in the sister-group Alcelaphini-Aepycerotini (Mammalia: Bovidae) |oclc = 10403493}}</ref> A 1999 [[phylogenetic]] study by Alexandre Hassanin (of the [[Centre national de la recherche scientifique|National Centre for Scientific Research, Paris]]) and colleagues, based on [[mtDNA|mitochondrial]] and [[nuclear DNA|nuclear]] analyses, showed that the impala forms a [[clade]] with the [[suni]] (''Neotragus moschatus''). This clade is sister to another formed by the [[bay duiker]] (''Cephalophus dorsalis'') and the [[klipspringer]] (''Oreotragus oreotragus'').<ref name="Hassanin">{{cite journal |last1 = Hassanin |first1 = A. |last2 = Douzery |first2 = E.J.P. |title = Evolutionary affinities of the enigmatic saola (''Pseudoryx nghetinhensis'') in the context of the molecular phylogeny of Bovidae |journal = [[Proceedings of the Royal Society B: Biological Sciences]] |date = 1999 |volume = 266 |issue = 1422 |pages = 893–900 |doi = 10.1098/rspb.1999.0720 |pmid = 10380679 |pmc = 1689916 }} {{open access}}</ref> An [[rRNA]] and [[spectrin|β-spectrin]] nuclear sequence analysis in 2003 also supported an association between ''Aepyceros'' and ''[[Neotragus]]''.<ref>{{cite journal |last1 = Kuznetsova |first1 = M.V. |last2 = Kholodova |first2 = M.V. |title = Revision of phylogenetic relationships in the Antilopinae subfamily on the basis of the mitochondrial rRNA and β-spectrin nuclear gene sequences |journal = Doklady Biological Sciences |year = 2003 |volume = 391 |issue = 1–6 |pages = 333–6 |doi = 10.1023/A:1025102617714 |pmid = 14556525 |s2cid = 30920084 |issn = 1608-3105 }}</ref> The following cladogram is based on the 1999 study:<ref name="Hassanin" />

{{clade | style=font-size:90%;line-height:100%;
|1={{clade
  |1={{clade
  |1={{clade
  |1={{clade
  |1=[[Sheep]] (''Ovis aries'')
  |2={{clade
  |1=[[Bontebok]] (''Damaliscus pygargus'')
  |2=[[Sable antelope]] (''Hippotragus niger'')
                 }}
             }}
  |2={{clade
  |1={{clade
  |1={{clade
  |1=[[Klipspringer]] (''Oreotragus oreotragus'')
  |2=[[Bay duiker]] (''Cephalophus dorsalis'')
                    }}
  |2={{clade
  |1='''Impala''' ('''''Aepyceros melampus''''')
  |2=[[Suni]] (''Neotragus moschatus'')
                    }}
                }}
             }}
          }}
  |2={{clade
  |1=[[Grant's gazelle]] (''Nanger granti'')
  |2=[[Mountain reedbuck]] (''Redunca fulvorufula'')
          }}
        }}
      }}
   }}

Up to six [[subspecies]] have been described, although only two are generally recognised on the basis of mitochondrial data.<ref name="Nersting">{{cite journal |first1 = L.G. |last1 = Nersting |first2 = P. |last2 = Arctander |title = Phylogeography and conservation of impala and greater kudu |journal = Molecular Ecology |volume = 10 |issue = 3 |pages = 711–9 |year = 2001 |doi = 10.1046/j.1365-294x.2001.01205.x |pmid = 11298982 |bibcode = 2001MolEc..10..711N |s2cid = 23102044 }}</ref> Though morphologically similar,<ref name=kingdon /> the subspecies show a significant [[genetic distance]] between them, and no [[hybrid (biology)|hybrids]] between them have been reported.<ref name=kingdon /><ref name="Lorenzen">{{cite journal |last1 = Lorenzen |first1 = E.D. |last2 = Arctander |first2 = P. |last3 = Siegismund |first3 = H.R. |title = Regional genetic structuring and evolutionary history of the impala (''Aepyceros melampus'') |journal = [[Journal of Heredity]] |date = 2006 |volume = 97 |issue = 2 |pages = 119–32 |doi = 10.1093/jhered/esj012 |pmid = 16407525 |doi-access = free }} {{open access}}</ref>
* ''A. m. melampus'' <small>Lichtenstein, 1812</small>: Known as the common impala, it occurs across eastern and southern Africa. The range extends from central [[Wildlife of Kenya|Kenya]] to [[Wildlife of South Africa|South Africa]] and westward into southeastern [[Wildlife of Angola|Angola]].
* ''A. m. petersi'' <small>[[José Vicente Barbosa du Bocage|Bocage]], 1879</small>: Known as the black-faced impala, it is restricted to southwestern Africa, occurring in northwestern [[Wildlife of Namibia|Namibia]] and southwestern Angola.

According to Vrba, the impala evolved from an alcelaphine ancestor. She noted that while this ancestor has [[Genetic divergence|diverged]] at least 18 times into various morphologically different forms, the impala has continued in its basic form for at least five million years.<ref name=vrba /><ref>{{cite book|last1=Arctander|first1=P.|last2=Kat|first2=P.W.|last3=Simonsen|first3=B.T.|last4=Siegismund|first4=H.R.|editor1-last=Smith|editor1-first=T.B.|editor2-last=Wayne|editor2-first=R.K.|title=Molecular Genetic Approaches in Conservation|date=1996|publisher=Oxford University Press|location=Oxford, UK|isbn=978-0-19-534466-0|pages=399–412|chapter=Population genetics of Kenyan impalas – consequences for conservation|chapter-url={{Google Books|id=QI8sdCHszY0C|page=399|plainurl=yes}} |oclc = 666957480}}</ref> Several [[fossil]] species have been discovered, including ''[[Aepyceros datoadeni|A. datoadeni]]'' from the [[Pliocene]] of [[Ethiopia]].<ref name="Geraads2012">{{cite journal |last1 = Geraads |first1 = D. |last2 = Bobe |first2 = R. |last3 = Reed |first3 = K. |title = Pliocene Bovidae (Mammalia) from the Hadar Formation of Hadar and Ledi-Geraru, Lower Awash, Ethiopia |journal = [[Journal of Vertebrate Paleontology]] |date = 2012 |volume = 32 |issue = 1 |pages = 180–97 |doi = 10.1080/02724634.2012.632046 |bibcode = 2012JVPal..32..180G |s2cid = 86230742 }}</ref> The oldest fossil discovered suggests its ancient ancestors were slightly smaller than the modern form, but otherwise very similar in all aspects to the latter. This implies that the impala has efficiently adapted to its environment since prehistoric times. Its gregarious nature, variety in diet, positive population trend, defence against [[tick]]s and [[symbiosis|symbiotic]] relationship with the tick-feeding [[oxpecker]]s could have played a role in preventing major changes in morphology and behaviour.<ref name=vrba />